


Quantum Mechanics of Love

by SprucePines



Category: Gravity Falls
Genre: Alternate Universe - Reverse Falls, F/M, Incest, Sibling Incest, Twincest, pinecest - Freeform, pinescest - Freeform
Language: English
Status: Completed
Published: 2017-08-12
Updated: 2017-08-12
Packaged: 2018-12-14 14:29:21
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,239
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11785089
Author URL: https://archiveofourown.org/users/SprucePines/pseuds/SprucePines
Summary: Mabel goes in search of a hidden pool of water that lets one converse with a parallel version of themselves. To date, my lone exploration into the "Reverse Falls" AU, albeit not truly set in that universe. Please feel free to comment if you like.





	Quantum Mechanics of Love

_Discovery number 726: The Quantum Pool. Found in a cave a short trek away from Lake Gravity Falls. Upon first glance its shimmering surface, which is present despite the incredibly low light of the cave itself, immediately attracts your attention. When you gaze into the pool, however, you aren’t greeted by your reflection. Instead you are greeted by the visage of another version of you from an alternate universe. Conversation is possible, if the wavelengths mesh just right, but repeated chats with the same alternate version seem to be impossible. Attempted no less than twelve times to chat with the Ford from a universe he identified as Dimension C-137 to no avail. Instead was greeted by, among other things, a female version of myself, a version that was half cyborg, one that spoke incredibly slow, one that spoke incredibly fast, one that seemed to be moving backwards, and one that was frantically begging for help. Something about his dimension being taken over by a malevolent being, but the connection was lost before he could identify his oppressor. More research is needed to see if the dimensional line up can be stabilized._

*********

Mabel shined the beam of her flashlight against the mossy walls of the cavern. The steady _drip…drip…drip…_ of water collecting in a small puddle were the only sounds she could hear apart from her own breathing. She’d been systematically searching the caves within range of the lake ever since she ran across Ford’s note in his old study. A trans-dimensional telephone, she thought. She imagined gabbing with various versions of herself, finding out what was the same, what was different. At one point, she would have loved to discuss boys with her various selves. Right now, though, there was only one boy she wanted to talk about.

She rounded a turn and came to a halt. Just up ahead, she could see what looked like light reflecting off of the walls. She flicked off her light and looked again. The light hadn’t changed. Considering how dark it was in the cave, she knew there shouldn’t be a light source, which could only mean…

She turned her light back on and slowly approached, mindful of cracks, holes, or loose moss. The last thing she wanted was to have a nasty spill or worse, to break something. She had made a point not to let anyone know where she was going, for fear of being followed. She had her cell phone, but if there were no signal this far in the caves, she could be galloping up diarrhea drive without a saddle.

She reached the entrance to another cavern, and she saw it with her own eyes. In the center was a roughly circular pit with what appeared to be an iridescent liquid filling it to the lip. It looked to have the same density as water, and perhaps that’s what it truly was. She wasn’t sure if it were the water, or the cave, or something else entirely that was causing the laser show. She mused for a second about playing some Pink Floyd on her iPod, but thought better of it. She’d wait until a more appropriate time…like when she and Dipper next watched The Wizard of Oz.

She crouched down and, placing her hands on the rim of the pit, leaned over and gazed into the pool. The reflected light danced on her face. It was actually quite enticing. She had a fleeting thought of Narcissus, so in love with himself that he stared at his own reflection until his death.

It was then that she realized that her reflection was, in fact, not her reflection. Or perhaps more accurately, not quite hers. It was certainly her face, there was no mistaking that, but virtually everything else seemed…backwards. This Mabel wore a cold, hard expression; there was a detachment behind her eyes, as if she didn’t care one whit for anyone or anything. Her mouth, rather than a joyous smile, was turned into a mirthless, sneering smirk, as if she were the only one to understand a particularly nasty joke and was privately amused that no one else got it. In her hair, she wore a black headband which had on one side…Mabel recognized that amulet!

It was this…Mirror Mabel that spoke first. “Just who the devil are you?” she demanded.

“Well, I’m you…sort of? I guess? You’re Mabel Pines, aren’t you?”

Mirror Mabel frowned as if she’d just smelled expired milk. “My name is Mabel Gleeful, and you would be wise to remember that, you impertinent, metal-mouthed miscreant!”

Now the amulet made sense. “Gleeful?” Mabel asked. “You mean as in Gideon?!”

“Gideon?” Mirror Mabel’s face instantly changed, becoming much more intrigued. “Tell me more about your Gideon. What’s he like? Is he as amusing as he is here?” Mabel was dismayed at her reaction to the mention of Gideon. She was growing less keen on that nickname for this version of herself. Someone with a demeanor like what Mabel _Gleeful_ was displaying wouldn’t appreciate the alliterative nature of the name.

“Never mind all that. It’s not important.” Inside, she laughed at her unintentional reference. “You’re still Mabel. Only a…Reverse Mabel, I guess. Yeah, that works.”

“Did you actually nickname me?”

“So that means you might still be able to help me,” Mabel went on not bothering to answer Reverse Mabel’s question. She had a feeling Reverse Mabel wouldn’t have anything nice to say if she did.

“And just why in the seventy-nine hells would I want to do that?”

Mabel blinked. She hadn’t really considered that. She had just assumed that whatever other Mabel she met, she would have a similar demeanor and willingness to help. “Um…out of the goodness of your heart?” she asked, hopeful. Reverse Mabel simply shook her head no, her arms folded in front of her chest. “Look, could you at least hear what I have to say, or will you just be a complete buttface?”

Even through the shimmering of the Quantum Pool, Mabel could see the amulet on Reverse Mabel’s headband begin to glow, along with her eyes. “I would slap the braces off of your teeth if you had said that to me in person!” She paused and took a deep breath. Both her eyes and the amulet ceased their glowing. “But I don’t really have anything else to do, so I suppose I can listen to you. For now.”

“Thank you,” Mabel said. She felt a sense of relief, though she couldn’t quite understand why. Reverse Mabel was in her own universe, she couldn’t do anything to hurt her…could she? Mabel thought it would probably be best not to test that theory, and decided to just get on with her question. “Okay, this question might sound a bit weird…maybe a bit gross and _blargh_ , but just hear me out, okay?” She took a deep breath, steeling herself. “Just how close are you with the Dipper of your universe?”

Reverse Mabel arched an eyebrow at her. “I’m not entirely sure I understand the question.”

“Um…well…I mean, are you and he…I mean, are the two of you…”

“Oh, you want to know if we’re in a relationship,” her doppelganger said flatly. “Why didn’t you just say so?”

Mabel blinked. She had said it as if it were nothing at all to her. “That’s it? No ‘EUGH! Absolutely not, and how dare you suggest such a disgusting idea, you mis…miscre…”

“Miscreant,” Reverse Mabel finished for her, “and the reason why I didn’t react that way should be plainly obvious.”

Mabel realized what she was saying. “Because the two of you are in a romantic relationship?”

Her mirror image shrugged. “I don’t know that I would characterize what Dipper and I have as a ‘romantic’ relationship, but we do have a sexual relationship, which I suppose could amount to the same thing depending on your point of view.” Her visage darkened. “You’re not one of the prudish Mabels, are you? One of those holier-than-thou types?”

Mabel shook her head quickly. “No, no, no. Nothing like that. Dipper and I have actually been together for a couple of years now. I just…wait. When you first saw me, you asked who I was. I thought this was your first time talking with another Mabel.”

“No, but that doesn’t mean I was expecting to have another version of me chatting with me in my vanity mirror today.”

“You mean, you’re not in the cave with the Quantum Pool?”

Reverse Mabel shook her head. “No, the pool reads your face and seeks out the corresponding version of you in whatever universe yours is aligned with at the time. As soon as they look into a reflective surface, you’ll see each other. Communication isn’t always possible, depending on what your target is looking into.”

“I see…I think…Anyway, no, Dipper and I are already together.”

“Then why are you asking me about it?”

“Because I want some advice.”

Reverse Mabel blinked. “You want relationship advice…from me?” Mabel nodded, to which Reverse Mabel laughed lightly. “Oh, my sweet summer child. I really don’t think I’m the best person to be asking that sort of advice from.”

Mabel scowled. “And why not?” she demanded.

“Because...oh how do the peasantry put it?” She thought a moment before she found the word she was looking for. “You’re too vanilla, Mabel.”

“’Vanilla?’” Mabel asked. “What’s that supposed to mean? I’m regularly having sex with my own twin brother. How is that vanilla?”

“I mean relatively speaking,” Reverse Mabel replied, “no pun intended. We might both be sharing more than just a bed with our brothers, but your bedroom habits and ours differ greatly, I’m sure.”

“That still makes you a good source of advice,” Mabel insisted, “because that’s one of the things I’m worried about.”

“You mean you’re looking to…spice things up with your brother?” Mabel nodded. “Again, I think you’re too vanilla.”

“Try me,” Mabel dared her double.

Reverse Mabel’s smirk reappeared. “We routinely tie each other down in bed, blindfolded, and toy with each other using different objects to stimulate the senses. Sometimes it’s something delicate, like a feather or even some fruits, and other times it’s coarse and rough, like fine grit sandpaper or even a leather strap across the backside. Part of the excitement comes from the receiving partner having no clue what’s about to touch their flesh.”

Mabel blushed deeply. She had said it so matter-of-factly. Reverse Mabel gestured to her. “You see? What did I tell you? No, my dear, come back another day when another universe is lined up with yours. I’m sure that Mabel’s advice will be of far better use to you than mine. Unless you get one of the prudes. If you do, do not let them talk to you about the Axolotl. You will never get a word in edgewise.”

“No, it’s not that,” Mabel said. “I was just…imagining Dipper tying me down and…not knowing what he was going to do to me…I think I might like to try that.”

Reverse Mabel grinned. Mabel thought it a bit unsettling, but she’d cast her die, she guessed. “I see. Perhaps you’re not as vanilla as I thought. Though some bits of that particular game might still be a bit extreme for you. What else…I have a series of different vibrators that Dipper likes to employ and watch my face contort.”

Mabel’s blush deepened.

“Once in a great while, he and I might bring a third person into our bed, though we always wipe their memory of it afterwards.”

Mabel pulled a sour milk face of her own. The idea of taking away someone’s memories like that seemed just…too cruel.

“I have a strap-on that Dipper sometimes lets me use on him.”

Mabel perked up at that one. “We’ve tried that, actually! Pacifica got it for me while she and I were still a thing.”

Reverse Mabel gaped at her. “You…and… _Pacifica?_ ”

“What? In this universe, she’s a semi-spoiled rich girl who’s slowly been reforming herself. I don’t know how she is in your world, but Pacifica isn’t all that bad here.”

Reverse Mabel shook her head. “I’ll just take your word on that. But you’ve pegged your brother, you say?”

Mabel nodded. “Pretty sure he liked it, but whenever I bring it up his face turns bright red and he changes the subject.”

The face in the pool laughed. “Oh, you are a bit adventurous after all. If he’s anything like my dear Dipper, he most certainly did enjoy it. He’s just too embarrassed to admit it. It took my brother a few times before he totally warmed up to the idea. In fact, I might have to ask him if we can do that tonight… Anyway, back to you. Does the Stanford of your universe have his collection of oddities and experiments?”

“Yes,” Mabel answered, nodding. “Why?”

“Dipper and I have found a few creative uses for some of them. There’s a shag rug that will swap consciousnesses between bodies via static electricity. It was one of the ways I got him to try pegging in the first place.”

Mabel imagined herself once again inhabiting her brother’s body, only this time using her penis to fuck his vagina. Each of them feeling a different set of pleasures than they’re used to. That had some definite possibilities, she thought.

“He also has a copier that creates clones. The machine on this side tends to jam up on occasion, though, and the clean-up can be horrendous if you make too many.”

Now Mabel envisioned a group of Dippers all surrounding her, each of them pleasuring her while she worked to pleasure all of them. Or even an entire room full of Dippers and Mabels, groups any and every way imaginable. But then she remembered how Tyrone and the other copies Dipper made had met their end. She couldn’t imagine the scene remaining very sexy after that.

“Take a look around that old house of his. He’s sure to have plenty of things squirreled away in there. Knowing how creative we Mabels are, I’m certain you can find some wonderful uses for some of them.”

“That we are,” Mabel said with a grin, which she was surprised to see Reverse Mabel matching. “Thank you, Mabel. I think you gave me some good ideas to start with.”

“You’re welcome,” Reverse Mabel replied. “I’m surprised to say this did not utterly waste my time. Usually, when another of us reaches me via their Quantum Pool, they turn out to be too ‘goody two shoes’ or ones who just want to prattle on and on about boys.”

Mabel chuckled nervously. “If I had learned of this just a few years ago, I probably would have been part of that second group. And maybe even the first, if you had sprung your relationship with your Dipper on me back then.”

“Sweet sister,” a new voice said, “here you are. What have you been doing?” This voice sounded like Dipper’s and yet something in its tone that made it very unlike her brother’s.

“Is that who I think it is?” Mabel asked.

“My Dipper? Why, yes. Would you like to meet him?” Mabel gulped, not entirely sure, but nodded anyway. Reverse Mabel turned to look out of the pool’s frame. “Come and see for yourself, dear brother,” she said.

A moment later, she was joined by someone who was at once Dipper and not Dipper. At least not the Dipper that Mabel recognized. His face was right and wrong at the same time. For one thing, he had his hair slicked back so his birthmark was plain to see. Her Dipper wouldn’t be caught dead showing that off. There was also the same cold detachment in his eyes that her own counterpart had. This was definitely Reverse Dipper.

Reverse Mabel pulled her brother in close and gave him a kiss. Mabel blushed. Even though she was, in a way, watching herself, there was something voyeuristic in watching this display. Reverse Dipper broke the kiss and regarded Mabel. “Quantum pool again?” he asked. His sister nodded. He leaned in close and examined her. Mabel blushed again under the scrutiny. “Hmm…rather fetching,” he said finally. “Wouldn’t you agree, sweet sister?”

His twin looked at him with a look of mock indignation. “Well, she’s certainly attractive, yes. She’s a Mabel, after all…though I can’t say I agree with her fashion sense. Why, just what are you thinking?”

“Well, the spell is nearly complete. Why not this one and her brother?”

Mabel furrowed her brown. What? What spell? What about her and Dipper?

Reverse Mabel pondered his words for a moment. “Perhaps…if we can attenuate the spell to her universe…yes, perhaps hers will do nicely.”

“Um, what are the two of you talking about?” Mabel asked.

Her reflection smirked at her. “Oh, you may find out soon enough, Mabel my sweet. Or perhaps you won’t. That remains to be seen.” The image in the pool began to distort, breaking apart much like a satellite signal in a rainstorm. “Oh dear, it seems our dimensions are moving out of synch. Remember what I told you, though, Mabel. I’m sure it will come in very handy with your brother. And who knows? Perhaps we’ll see each other very…very…soon.” She tittered as her image faded from the pool.

The shimmering had stopped, too, Mabel noticed. Must only happen when dimensions are lined up right, she guessed. She stayed in her spot and waited, unsure if perhaps the next dimension over would come into range right away or not. After several minutes of sitting with no activity from the pool, she rationalized that she’d likely have to come back another time if she wished to have a chat with another Mabel. If the majority of them were like Reverse Mabel described them, though, maybe that wasn’t such a good idea.

She took her time walking home, using the time to reflect on what her reflection had said. Good pun, she told herself when she thought of that one. Why, thank you, me, she thanked herself, too. Some of what she said troubled Mabel. Not the sex stuff; those were nearly all things she was excited to try with Dipper. No, it was the bit at the end. What were the Reverse Twins, as she’d dubbed them, talking about?

What spell?

What does attenuate mean, and why did that sound like something she did not want to happen with her universe?

And that last statement, that they might see each other very…very…soon. There was something very…very…ominous in those words, though Mabel would be damned if she could say exactly why that was so.

Eventually, she stepped through the last stand of trees and was within sight of the Mystery Shack. From over by the totem pole, she could see her brother sitting on the porch in Stan’s old easy chair. The sight of him convinced her to put a pin on her troubled thoughts. It was probably just grandstanding by her “evil goatee universe” self, being all malevolent and _MWAHAHAHAHAHA!!_ It probably wouldn’t come to anything.

For now, though, there were some things she was looking forward to trying with her brother.

 


End file.
